The present invention relates generally to venting assemblies for sealed body fluid drainage devices and more particularly to venting assemblies normally associated with drainage units as used in urinary collections systems and the like.
Such systems utilize a portable and disposable sealed container for temporarily storing body fluids such as urine draining therein through a catheter tube having one end inserted through the human urethra to the bladder and a second discharge end directed into the sealed container. The drainage container will have air therein at the beginning of the drainage operation. To prevent entrapment of air within the sealed container and to alleviate pressure buildup as drainage progresses, various means have been provided for venting these containers.
While the venting or breather assemblies commonly found in closed drainage containers perform adequately in venting the gas trapped or contained within the container, the known devices tend to clog, and are relatively ineffective in precluding bacterial infection caused by the entrance of bacteria through the venting or breather assembly. Such bacteria entering the drainage system may well travel upward to the bladder, urethra, and kidneys infecting same and causing such problems as urinary sepsis, cystitis, and pyelonephritis.
Examples of known venting means will be seen in U.S. Pat. No. 3,998,255 and U.S. Pat. No. 3,523,408. U.S. Pat. No. 3,998,255 discloses a breather assembly for a sealed container made from a material comprised of a woven substrate of synthetic material such as nylon with a coating of a copolymer such as polyvinyl chloride. A filter constructed with wetting and non-wetting filter membranes is shown in U.S. Pat. No. 3,523,408 to Rosenberg. However, in the Rosenberg patent, a liquid is introduced between a pair of equally large, facing filter membranes, one of which is liquid-wetting and gas-repellent when saturated with liquid, and the other of which is liquid-repellent and is capable of passing gas, so that only liquid passes through the liquid-wetted filter, and only gas passes through the liquid-repellent filter.